Paenibacillus sabinae sp. nov., a nitrogen-fixing species isolated from the rhizosphere soils of shrubs

Abstract

Five novel endospore-forming, nitrogen-fixing bacterial strains were isolated from the rhizosphere soils of plants of the species Sabina squamata, Weigela florida and Zanthoxylum simulans. A phylogenetic analysis based on 16S rRNA gene sequences revealed that the five strains formed a distinct cluster within the genus Paenibacillus. These novel strains showed the highest levels (96.2–98.2 %) of 16S rRNA gene sequence similarity with Paenibacillus azotofixans. However, the DNA–DNA relatedness between these novel strains and P. azotofixans was 12.9–29.5 %. The DNA G+C contents of the five strains were found to be 51.9–52.9 mol%. Phenotypic analyses showed that a significant feature of the novel strains (differentiating them from P. azotofixans and other Paenibacillus species) is that all of them were unable to produce acid and gas from various carbohydrates such as glucose, sucrose, lactose and fructose. Anteiso-branched C15 : 0 was the major fatty acid present in the novel type strain. On the basis of these data, the five novel strains represent a novel species of the genus Paenibacillus, for which the name Paenibacillus sabinae sp. nov. is proposed. The type strain is T27T (=CCBAU 10202T=DSM 17841T).